Computers connected to networks are vulnerable to network based malicious computer code attacks, such as worms, viruses and Trojan horses. As used herein, “malicious computer code” is any code that enters a computer without an authorized user's knowledge and/or without an authorized user's consent. Network based malicious computer code attacks attempt to transmit malicious code to a target computer, and then run the malicious code on that target computer.
Some existing security mechanisms attempt to distinguish between malicious code and benevolent code. Such mechanisms can block transmissions containing what is suspected to be malicious code. Such mechanisms can be very useful under certain circumstances. However, distinguishing between malicious code and benevolent code can be difficult. If the algorithm used is too aggressive, a certain amount of desired, benevolent code can falsely be classified as malicious, and blocked from reaching the target computer. On the other hand, if the algorithm used is not aggressive enough, some malicious code can be incorrectly classified as benevolent, and thus allowed to enter and infect the target computer.
There are circumstances under which attempting to make such a distinction is neither necessary nor desirable. Specifically, there are specific circumstances under which no code should be transmitted to a target computer. What is needed are methods, computer readable media and systems that, under the appropriate circumstances and only under the appropriate circumstances, block all incoming network traffic containing code.